Oxygen concentrator



FIG. 1 is a top perspective view of an oxygen concentrator of thepresent invention;

FIG. 2 is a top view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a first side view thereof;

FIG. 6 is a second side view thereof; and,

FIG. 7 is a rear view thereof.

The ornamental design for an oxygen concentrator, as shown anddescribed.